Accurate Simulation of Transistor-Level Variability for the Purposes of TCAD-Based Device-Technology Cooptimization

Abstract

In this paper we illustrate how the predictive Technology Computer Aided Design (TCAD) process device simulation can be used to evaluate process, statistical, and timedependent variability at the early stage of the development of new technology. This is critically important for the delivery of accurate early Process Design Kits, including process variability, statistical variability, time-dependent variability (degradation) and their interactions and correlations. This is also critical to the TCAD-based Design-Technology Co-Optimisation (DTCO). To accomplish this task, the fast, large area Coventor virtual fabrication platform SEMulator3D was integrated in the Gold-StandradSimulations TCAD-based DTCO tool chain. Published data for Intel 22-nm FinFET technology are used to illustrate and validate the results of the TCAD process and device simulation, the compact model extraction, and the statistical circuit simulation.

Threshold Voltage Statistical Variability and Its Sensitivity to Critical Geometrical Parameters in Ultrascaled InGaAs and Silicon FETs

“…The number of dopant atoms in a given volume follows the Poisson distribution with an average value equal to the nominal number of dopants in that volume [27]. WFF is caused by intrinsic granularity of the gate metal, and modeled by assuming TiN gate metal characterized by two major grain orientations with a workfunction difference of 0.2 eV and an associated probability of 0.4/0.6 for the lowest/highest workfunction, respectively [12,18]. The number of metal grains in the gate region follows a Poisson distribution with an average value calculated using the average grain size.…”

“…The methodology used in our analysis is an advancement over the approaches previously reported in literature, in that we simultaneously considered all the relevant sources of statistical variability, as well as their dependence on the most critical geometrical parameters. Previous works considered only Si channel material [12,[14][15][16][17][18][19][20], fewer variability sources and/or sensitivity parameters [17,[19][20][21][22][23][24], and devices not as aggressively scaled as in our investigation [12,15,17].…”